For natural numbers x, y and z, define A to consist of triples (x, y, z) such that x + y = z. Let L = {((p,..., Pn)) : P1, ..., Pn N and there exists pi, Pj and pk such that (Pi, Pj, Pk) E A}. Show that L is in NP. Pk Make sure that the runtime of verifier is polynomial in input size.